NOAA/WDS Paleoclimatology - Equatorial Pacific Planktonic Foraminifera Carbon and Oxygen Isotope Data

The occurrence of carbon isotope minima at the beginning of glacial terminations is a common feature of planktic foraminifera carbon isotopic records from the Indo-Pacific, sub-Antarctic, and South Atlantic. We use the delta 13C record of a thermocline-dwelling foraminifera, Neogloboquadrina dutertrei, and surface temperature estimates from the eastern equatorial Pacific to demonstrate that the onset of delta 13C minimum events and the initiation of Southern Ocean warming occurred simultaneously. Timing agreement between the marine record and the delta 13C minimum in an Antarctic atmospheric record suggests that the deglacial events were a response to the breakdown of surface water stratification, renewed Circumpolar Deep Water upwelling, and advection of low delta 13C waters to the convergence zone at the sub-Antarctic front. On the basis of age agreement between the absolute delta 13C minimum in surface records and the shift from low to high delta 13C in the deep South Atlantic, we suggest that the delta 13C rise that marks the end of the carbon isotope minima was due to the resumption of North Atlantic Deep Water influence in the Southern Ocean.